The present invention concerns the design of lumped circuit circulators operating in a frequency band of the metric, decimetric or centimetric range.
French Pat. No. 2,185,896, filed on May 23, 1973, described a wideband circulator, which is illustrated in FIGS. 1A to 1C and which comprises an internal shield 11 surrounding two ferrite discs 10 a substrate 14 on which is deposited a printed circuit 15 forming the non reciprocal propagation medium, and two magnets 13 side of a printed circuit. Widening of the band is obtained by connecting shield 11, with a capacitance C.sub.s in relation to the ferrite discs, to three inductors L'.sub.s one end which is connected to casing 12, as illustrated in FIG. 1b. FIG. 1c illustrates the printed circuit composed of a central disc 16 which is in contact with shielf 11 and is connected to the three leads 17 constituting the inductances L'.sub.s, each of which is terminated by a stud 18 which establishes the contact with the casing 12. The circuit disposed between the ferrite discs 10 is connected to the ports of the circulator.
The object of the present invention is to provide a lumped circuit circulator which comprises a continuously tunable band widening device.